In general, a refrigerator is provided with a damper device in the cold air passage, such as a duct, to regulate the flow of cold air inside the refrigerator and maintain the temperature within the refrigerator at a preset temperature.
The present invention has been made to improve the prior art disclosed in Korean Registered Utility Model No. 20-0285567 in the name of the present applicant, entitled “REFRIGERATOR DAMPER USING GEAR-EQUIPPED STEP MOTOR”, the disclosure of which will now be described with reference to FIG. 1.
As shown in FIG. 1, the refrigerator damper 100 using a gear-equipped step motor a frame 110 installed in the cold air passage and provided with an opening 114, a baffle 130 adapted to regulate the flow of cold air in the opening 114 of the frame 110, and a gear-equipped step motor 120 installed in a motor case formed on a side of the frame 110 to rotate the baffle 130 a predetermined angle based on the temperature condition of the refrigerator.
The baffle 130 is a square plate and is adapted to be rotated a predetermined angle by the gear-equipped step motor 120 to open/close the opening 114 of the frame 110. The baffle 130 has an output shaft cap 132 formed on a side thereof to be inserted into and coupled to the output shaft 122 of the gear-equipped step motor 120 and a rotation support shaft cap 134 formed on the other side thereof into which the rotation support shaft 112 formed on the frame 110 is inserted and coupled to support the rotation of the output shaft.
As currents are applied to the gear-equipped step motor 120, it generates a rotation force which is transmitted to the output shaft cap 132 inserted and coupled to the output shaft 122. The baffle 130 is then reciprocally rotated by the rotation force within a predetermined range of rotation angle to open/close the opening 114 and control the outflow of the cold air.
When the baffle 130 completely closes the opening 114, the flow of cold air is interrupted and, when the baffle 130 completely opens the opening 114, the flow of cold air is maximized. As such, the amount of cold air flowing into the refrigerating chamber or the freezing chamber is regulated.
When the baffle position (rotation angle) of the damper is controlled by the conventional gear-equipped step motor, however, the gear-equipped step motor may operate erroneously and the rotation angle of the baffle may exceed a desired range. Thus, the opening/closing operation of the baffle becomes unreliable frequently.
Particularly, the step motor has a preset rotation angle corresponding to each electrical input signal (pulse) and is suitable for position control. When a predetermined frequency or pulse is applied to the gear-equipped step motor for opening operation of the baffle, the absence of a means for limiting the maximum rotation angle of the baffle generates frequent errors in the baffle position.
Such errors in the baffle position due to the gear-equipped step motor make the opening/closing operation of the baffle inaccurate. When the baffle incompletely opens the opening, the circulation of cold air within the refrigerator is disturbed and, when the baffle incompletely closes the opening, the cold air leaks out and the efficiency of the refrigerator degrades.
When the baffle position of the damper is controlled by the gear-equipped step motor, it is difficult to install a means for limiting the maximum rotation angle of the baffle, e.g., a stopper, inside the gear-equipped step motor. Even when such a means is installed therein, it is not easy to adjust the initial position when the damper is assembled.